/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.classfile.editor;

import proguard.classfile.*;
import proguard.classfile.attribute.*;
import proguard.classfile.attribute.visitor.AttributeVisitor;
import proguard.classfile.constant.RefConstant;
import proguard.classfile.constant.visitor.ConstantVisitor;
import proguard.classfile.instruction.*;
import proguard.classfile.instruction.visitor.InstructionVisitor;
import proguard.classfile.util.SimplifiedVisitor;
import proguard.classfile.visitor.MemberVisitor;

/**
 * This MemberVisitor fixes all inappropriate bridge access flags of the program methods that it visits, checking
 * whether the methods to which they bridge have the same name. Some compilers, like in Eclipse and in later versions of
 * JDK 1.6, complain if they can't find the method with the same name.
 *
 * @author Eric Lafortune
 */
public class BridgeMethodFixer extends SimplifiedVisitor
    implements MemberVisitor, AttributeVisitor, InstructionVisitor, ConstantVisitor {
    private static final boolean DEBUG = false;

    // Return values for the visitor methods.
    private String bridgedMethodName;

    // Implementations for MemberVisitor.

    public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod) {
        if ((programMethod.getAccessFlags() & ClassConstants.ACC_BRIDGE) != 0) {
            programMethod.attributesAccept(programClass, this);
        }
    }

    // Implementations for AttributeVisitor.

    public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}

    public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute) {
        // Go over the instructions of the bridge method.
        codeAttribute.instructionsAccept(clazz, method, this);
    }

    // Implementations for InstructionVisitor.

    public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset,
        Instruction instruction) {}

    public void visitConstantInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset,
        ConstantInstruction constantInstruction) {
        switch (constantInstruction.opcode) {
            case InstructionConstants.OP_INVOKEVIRTUAL:
            case InstructionConstants.OP_INVOKESPECIAL:
            case InstructionConstants.OP_INVOKESTATIC:
            case InstructionConstants.OP_INVOKEINTERFACE:
                // Get the name of the bridged method.
                clazz.constantPoolEntryAccept(constantInstruction.constantIndex, this);

                // Check if the name is different.
                if (!method.getName(clazz).equals(bridgedMethodName)) {
                    if (DEBUG) {
                        System.out.println("BridgeMethodFixer: [" + clazz.getName() + "." + method.getName(clazz)
                            + method.getDescriptor(clazz) + "] does not bridge to [" + bridgedMethodName + "]");
                    }

                    // Clear the bridge flag.
                    ((ProgramMethod)method).u2accessFlags &= ~ClassConstants.ACC_BRIDGE;
                }
                break;
        }
    }

    // Implementations for ConstantVisitor.

    public void visitAnyMethodrefConstant(Clazz clazz, RefConstant refConstant) {
        bridgedMethodName = refConstant.getName(clazz);
    }
}